How does limbic info get to the hypothalamus?

What are circumventricular organs?

regions of the brain that lack a blood brain barrier and allow blood borne signals to reach chemosensitive neurons.Also allow them to use neurohumoral/hormonal mechanisms to control peripheral function

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What is the subfornical organ?

a circumventricular organ around the anterior wall of the third ventricle that contains angiotensin II receptors that induce drinking

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What is the organum vasculosum of the lamina terminalis? OVLT

may have neuroendocrine function and may contain osmoreceptors for vasopressin releasecircumventricular organ

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What is the area postrema?

circumventricular organ in the walls of the fourth ventricle in the medulla. It is the chemoreceptor trigger zone for vomiting.

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What is the median eminence?

part of the pituitary stalk. major route oc fommunication between the hypothalamic-pituitary system and target effector organs. circumventricular organ.

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What is the medial forebrain bundle?

group of axons running rostrocaudally through the lateral hypothalamus. conntects the hypothalamus with the brainstem and basal forebrain. important for olfactory input and monoamine input

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What is the dorsal longitudinal fasciculus?

output of hypothalamus to the autonomic cell groups in the brainstem and spinal cord.

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What are the connections between the hypothalamus and the anterior and posterior pituitary? What is the embryological origin?

posterior pituitary is a true neuronal connection derived from neural ectoderm. As such, communication is very fast. called the neurohypophysis.anterior pituitary is a hormonal connection derived from oral ectoderm/Rathke's pouch The anterior pituitary is also called the adenohypophysis. Message from the hypothalamus conveied by the portal plexus. These are slower responses.

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What hormones are released by the neurohypophysis?

(posterior pituitary)oxytocin and vasopressin (antidiuretic hormone)

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Where are oxytocin and vassopressin synthesized?

magnocellular neurons of the supraoptic and paraventricular nucleus

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How do oxytocin and vasopressin get to the posterior pituitary? How do they get to the body?

from the supraoptic and paraventricular nuclei, they are transported in the tuberohypophyseal or (more important) supraopticohypophysial tract. these are basically axons from these nuclei. the hormones are released after an AP goes down the axon.they get to the rest of the body via release into a capillary plexus and then transport to the general circulation by the hypophyseal veins

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What does ADH/vasopressin do?

binds to receptors in the collecting duct of the kidney and promotes reabsorption of water. substances that suppress ADH (like alcohol) promote diuresis. also helpful during hemorrhage as a vasoconstrictor

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What is diabetes insipidus? What are the etiologies?

impaired or absent ADH secretion.excessive drinking and urination seen. This is called central diabetes insipidis.nephrogenic diabetes insipidus is when the kidneys don't respond to ADH